Refactor util clock into it's own pkg

pkg/util/clock/clock_test.go

@@ -0,0 +1,184 @@
+/*
+Copyright 2015 The Kubernetes Authors.
+
+Licensed under the Apache License, Version 2.0 (the "License");
+you may not use this file except in compliance with the License.
+You may obtain a copy of the License at
+
+    http://www.apache.org/licenses/LICENSE-2.0
+
+Unless required by applicable law or agreed to in writing, software
+distributed under the License is distributed on an "AS IS" BASIS,
+WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+See the License for the specific language governing permissions and
+limitations under the License.
+*/
+
+package clock
+
+import (
+	"testing"
+	"time"
+)
+
+func TestFakeClock(t *testing.T) {
+	startTime := time.Now()
+	tc := NewFakeClock(startTime)
+	tc.Step(time.Second)
+	now := tc.Now()
+	if now.Sub(startTime) != time.Second {
+		t.Errorf("input: %s now=%s gap=%s expected=%s", startTime, now, now.Sub(startTime), time.Second)
+	}
+
+	tt := tc.Now()
+	tc.SetTime(tt.Add(time.Hour))
+	if tc.Now().Sub(tt) != time.Hour {
+		t.Errorf("input: %s now=%s gap=%s expected=%s", tt, tc.Now(), tc.Now().Sub(tt), time.Hour)
+	}
+}
+
+func TestFakeClockSleep(t *testing.T) {
+	startTime := time.Now()
+	tc := NewFakeClock(startTime)
+	tc.Sleep(time.Duration(1) * time.Hour)
+	now := tc.Now()
+	if now.Sub(startTime) != time.Hour {
+		t.Errorf("Fake sleep failed, expected time to advance by one hour, instead, its %v", now.Sub(startTime))
+	}
+}
+
+func TestFakeAfter(t *testing.T) {
+	tc := NewFakeClock(time.Now())
+	if tc.HasWaiters() {
+		t.Errorf("unexpected waiter?")
+	}
+	oneSec := tc.After(time.Second)
+	if !tc.HasWaiters() {
+		t.Errorf("unexpected lack of waiter?")
+	}
+
+	oneOhOneSec := tc.After(time.Second + time.Millisecond)
+	twoSec := tc.After(2 * time.Second)
+	select {
+	case <-oneSec:
+		t.Errorf("unexpected channel read")
+	case <-oneOhOneSec:
+		t.Errorf("unexpected channel read")
+	case <-twoSec:
+		t.Errorf("unexpected channel read")
+	default:
+	}
+
+	tc.Step(999 * time.Millisecond)
+	select {
+	case <-oneSec:
+		t.Errorf("unexpected channel read")
+	case <-oneOhOneSec:
+		t.Errorf("unexpected channel read")
+	case <-twoSec:
+		t.Errorf("unexpected channel read")
+	default:
+	}
+
+	tc.Step(time.Millisecond)
+	select {
+	case <-oneSec:
+		// Expected!
+	case <-oneOhOneSec:
+		t.Errorf("unexpected channel read")
+	case <-twoSec:
+		t.Errorf("unexpected channel read")
+	default:
+		t.Errorf("unexpected non-channel read")
+	}
+	tc.Step(time.Millisecond)
+	select {
+	case <-oneSec:
+		// should not double-trigger!
+		t.Errorf("unexpected channel read")
+	case <-oneOhOneSec:
+		// Expected!
+	case <-twoSec:
+		t.Errorf("unexpected channel read")
+	default:
+		t.Errorf("unexpected non-channel read")
+	}
+}
+
+func TestFakeTick(t *testing.T) {
+	tc := NewFakeClock(time.Now())
+	if tc.HasWaiters() {
+		t.Errorf("unexpected waiter?")
+	}
+	oneSec := tc.Tick(time.Second)
+	if !tc.HasWaiters() {
+		t.Errorf("unexpected lack of waiter?")
+	}
+
+	oneOhOneSec := tc.Tick(time.Second + time.Millisecond)
+	twoSec := tc.Tick(2 * time.Second)
+	select {
+	case <-oneSec:
+		t.Errorf("unexpected channel read")
+	case <-oneOhOneSec:
+		t.Errorf("unexpected channel read")
+	case <-twoSec:
+		t.Errorf("unexpected channel read")
+	default:
+	}
+
+	tc.Step(999 * time.Millisecond) // t=.999
+	select {
+	case <-oneSec:
+		t.Errorf("unexpected channel read")
+	case <-oneOhOneSec:
+		t.Errorf("unexpected channel read")
+	case <-twoSec:
+		t.Errorf("unexpected channel read")
+	default:
+	}
+
+	tc.Step(time.Millisecond) // t=1.000
+	select {
+	case <-oneSec:
+		// Expected!
+	case <-oneOhOneSec:
+		t.Errorf("unexpected channel read")
+	case <-twoSec:
+		t.Errorf("unexpected channel read")
+	default:
+		t.Errorf("unexpected non-channel read")
+	}
+	tc.Step(time.Millisecond) // t=1.001
+	select {
+	case <-oneSec:
+		// should not double-trigger!
+		t.Errorf("unexpected channel read")
+	case <-oneOhOneSec:
+		// Expected!
+	case <-twoSec:
+		t.Errorf("unexpected channel read")
+	default:
+		t.Errorf("unexpected non-channel read")
+	}
+
+	tc.Step(time.Second) // t=2.001
+	tc.Step(time.Second) // t=3.001
+	tc.Step(time.Second) // t=4.001
+	tc.Step(time.Second) // t=5.001
+
+	// The one second ticker should not accumulate ticks
+	accumulatedTicks := 0
+	drained := false
+	for !drained {
+		select {
+		case <-oneSec:
+			accumulatedTicks++
+		default:
+			drained = true
+		}
+	}
+	if accumulatedTicks != 1 {
+		t.Errorf("unexpected number of accumulated ticks: %d", accumulatedTicks)
+	}
+}